Pharmaceutical industry payments and delivery of non-recommended and low value cancer drugs: population based cohort study

OBJECTIVE

To estimate the association between oncologists' receipt of payments from the pharmaceutical industry and delivery of non-recommended or low value interventions among their patients.

DESIGN

Cohort study.

SETTING

Fee-for-service Medicare claims.

PARTICIPANTS

Medicare beneficiaries with a diagnosis of incident cancer (new occurrence of a cancer diagnosis code in proximity to claims for cancer treatment, and no such diagnosis codes during a ≥1 year washout period) during 2014-19, who met additional requirements identifying them as at risk for one of four non-recommended or low value interventions: denosumab for castration sensitive prostate cancer, granulocyte colony stimulating factors (GCSF) for patients at low risk for neutropenic fever, nab-paclitaxel for cancers with no evidence of superiority over paclitaxel, and a branded drug in settings where a generic or biosimilar version was available.

MAIN OUTCOME MEASURES

Receipt of the non-recommended or low value drug for which the patient was at risk. The primary association of interest was the assigned oncologist's receipt of any general payments from the manufacturer of the corresponding non-recommended or low value drug (measured in Open Payments) within 365 days before the patient's index cancer date. The two modeling approaches used were general linear model controlling for patients' characteristics and calendar year, and general linear model with physician level indicator variables.

RESULTS

Oncologists were in receipt of industry payments for 2962 of 9799 patients (30.2%) at risk for non-recommended denosumab (median $63), 76 747 of 271 485 patients (28.3%) at risk for GCSF (median $60); 18 491 of 86 394 patients (21.4%) at risk for nab-paclitaxel (median $89), and 4170 of 13 386 patients (31.2%) at risk for branded drugs (median $156). The unadjusted proportion of patients who received non-recommended denosumab was 31.4% for those whose oncologist had not received payment and 49.5% for those whose oncologist had (prevalence difference 18.0%); the corresponding values for GCSF were 26.6% v 32.1% (5.5%), for nab-paclitaxel were 7.3% v 15.1% (7.8%), and for branded drugs were 88.3% v 83.5% (-4.8%). Controlling for patients' characteristics and calendar year, payments from industry were associated with increased use of denosumab (17.5% (95% confidence interval 15.3% to 19.7%)), GCSF (5.8% (5.4% to 6.1%)), and nab-paclitaxel (7.6% (7.1% to 8.1%)), but lower use of branded drugs (-4.6% (-5.8% to -3.3%)). In physician level indicator models, payments from industry were associated with increased use of denosumab (7.4% (2.5% to 12.2%)) and nab-paclitaxel (1.7% (0.9% to 2.5%)), but not with GCSF (0.4% (-0.3% to 1.1%)) or branded drugs (1.2% (-6.0 to 8.5%)).

CONCLUSIONS

Within some clinical scenarios, industry payments to physicians are associated with non-recommended and low value drugs. These findings raise quality of care concerns about the financial relationships between physicians and industry.

Low-Dose Continuous 5-Fluorouracil Combined with Leucovorin, nab-Paclitaxel, Oxaliplatin, and Bevacizumab for Patients with Advanced Pancreatic Cancer: A Retrospective Analysis

BACKGROUND

Continuous-infusion 5-fluorouracil (5FU) and calcium leucovorin plus nab-paclitaxel and oxaliplatin have been shown to be active in patients with pancreatic cancer. As a protracted low-dose infusion, 5FU is antiangiogenic, and has synergy with bevacizumab. As shown in the treatment of breast cancer, bevacizumab and nab-paclitaxel are also synergetic.

OBJECTIVE

In this paper we retrospectively analyze the survival of 65 patients with advanced pancreatic cancer who were treated with low-dose continuous (metronomic) chemotherapy given in conjunction with conventional anti-VEGF therapy.

PATIENTS AND METHODS

Since July of 2008, we have treated 65 patients with 5FU (180 mg/m2/day × 14 days) via an ambulatory pump. Calcium leucovorin (20 mg/m2 IV), nab-paclitaxel (60 mg/m2) IV as a 30-min infusion, and oxaliplatin (50 mg/m2) IV as a 60-min infusion were given on days 1, 8, and 15. Bevacizumab (5 mg/kg) IV over 30 min was administered on days 1 and 15. Cycles were repeated every 28-35 days. There were 42 women and 23 men, and the median age was 59 years. Forty-six patients had stage IV disease.

RESULTS

The median survival was 19 months, with 82% of patients surviving 12 months or longer. The overall response rate was 49%. There were 28 patients who had received prior treatment, 15 of whom responded to therapy. Fifty-two patients had elevated CA 19-9 prior to treatment. Of these, 21 patients had 90% or greater reduction in CA 19-9 levels. This cohort had an objective response rate of 71% and a median survival of 27 months. Thirty patients stopped treatment due to disease progression, and an additional 22 stopped because of toxicity. One patient died while on therapy.

CONCLUSIONS

This non-gemcitabine-based regimen resulted in higher response rates and better survival than what is commonly observed with therapy given at conventional dosing schedules. Low-dose continuous (metronomic therapy) cytotoxic chemotherapy combined with antiangiogenic therapy is safe and effective.

Paclitaxel injection concentrate for nanodispersion versus nab-paclitaxel in women with metastatic breast cancer: a multicenter, randomized, comparative phase II/III study

Paclitaxel is widely used in the treatment of patients with metastatic breast cancer (MBC). Formulations of paclitaxel contain surfactants and solvents or albumin derived from human blood. The use of co-solvents such as polyoxyethylated castor oil is thought to contribute to toxicity profile and hypersensitivity reactions as well as leaching of plasticizers from polyvinyl chloride bags and infusion sets. Currently, nab-paclitaxel, an albumin-bound paclitaxel in nanometer range continues to be the preferred taxane formulation used in clinic. This study (CTRI/2010/091/001116) investigated the efficacy and tolerability of a polyoxyethylated castor oil- and albumin-free formulation of paclitaxel [paclitaxel injection concentrate for nanodispersion (PICN)] compared with nab-paclitaxel in women with refractory MBC. The current study was a multicenter, open-label, parallel-group, randomized, comparative phase II/III trial evaluating the efficacy and safety of PICN (260 mg/m(2) [n = 64] and 295 mg/m(2) [n = 58] every 3 weeks) compared with nab-paclitaxel (260 mg/m(2) every 3 weeks [n = 58]) in women 18 and 70 years old with confirmed MBC. Overall response rate (ORR) was assessed with imaging every 2 cycles. An independent analysis of radiologic data was performed for evaluable patients. Progression-free survival (PFS) was a secondary efficacy measure. Independent radiologist-assessed ORRs in the evaluable population of women aged ≥70 years were 35, 49, and 43 % in the PICN 260 mg/m(2), PICN 295 mg/m(2), and nab-paclitaxel 260 mg/m(2) arms, respectively. Median PFS in the evaluable population was 23, 35, and 34 weeks in the PICN 260 mg/m(2), PICN 295 mg/m(2), and nab-paclitaxel 260 mg/m(2) arms, respectively. Adverse events occurred in similar proportions of patients across treatment arms. Hypersensitivity reactions were not frequently observed with the clinical use of PICN across the treatment cohorts. In women with metastatic breast cancer, PICN at 260 and 295 mg/m(2) every 3 weeks was effective and well tolerated and showed similar tolerability compared with nab-paclitaxel 260 mg/m(2) every 3 weeks. Statistically, significant differences were not observed in the PICN and nab-paclitaxel treatment arms for radiologist-assessed ORR or median PFS. The novel paclitaxel formulation, PICN, offers apart from efficacy, potential safety advantage of decreased use of corticosteroid pretreatment and the absence of the risk of transmission of blood product-borne disease.

Incidence and risk of peripheral neuropathy with nab-paclitaxel in patients with cancer: a meta-analysis

Nab-paclitaxel, a Cremophor EL-free formulation of paclitaxel, is used to treat various malignancies. Peripheral neuropathy is one of its major toxicities, although the overall incidence remains unclear. We performed a meta-analysis to calculate the incidence of peripheral neuropathy in cancer patients treated with nab-paclitaxel and to compare the relative risk (RR) with conventional taxanes. The electronic databases were searched for relevant clinical trials. Eligible studies included phase II and III prospective clinical trials of cancer patients treated with nab-paclitaxel with toxicity profile on peripheral neuropathy. Statistical analyses were done to calculate summary incidences, RRs and 95% confidence intervals (CI), using fixed-effects or random-effects models based on the heterogeneity of the included studies. Nineteen trials were selected for the meta-analysis, yielding a total of 2878 cancer patients. The overall incidences of peripheral neuropathy (all-grade) was 51.0% (95% CI: 45.1-57.6%), and that of high-grade peripheral neuropathy was 12.4% (9.8-15.7%). The RRs of peripheral neuropathy of nab-paclitaxel compared to taxanes were not increased for all-grade and high-grade peripheral neuropathy. Nab-paclitaxel is associated with an increased risk of developing peripheral neuropathy. Future clinical studies are still needed to investigate the risk reduction and possible use of nab-paclitaxel.

Poly(2-oxazoline) based micelles with high capacity for 3rd generation taxoids: preparation, in vitro and in vivo evaluation

The clinically and commercially successful taxanes, paclitaxel and docetaxel suffer from two major drawbacks, namely their very low aqueous solubility and the risk of developing resistance. Here, we present a method that overcomes both drawbacks in a very simple manner. We formulated 3rd generation taxoids, able to avoid common drug resistance mechanisms with doubly amphiphilic poly(2-oxazoline)s (POx), a safe and highly efficient polymer for the formulation of extremely hydrophobic drugs. We found excellent solubilization of different 3rd generation taxoids irrespective of the drug's chemical structures with essentially quantitative drug loading and final drug to polymer ratios around unity. The small, highly loaded micelles with a hydrodynamic diameter of less than 100nm are excellently suited for parenteral administration. Moreover, a selected formulation with the taxoid SB-T-1214 is about one to two orders of magnitude more active in vitro than paclitaxel in the multidrug resistant breast cancer cell line LCC6-MDR. In contrast, in wild-type LCC6, no difference was observed. Using a q4d×4 dosing regimen, we also found that POx/SB-T-1214 significantly inhibits the growth of LCC6-MDR orthotropic tumors, outperforming commercial paclitaxel drug Taxol and Cremophor EL formulated SB-T-1214.

nab-Paclitaxel dose and schedule in breast cancer

nab-Paclitaxel is approved for the treatment of metastatic breast cancer on an every-3-week schedule based on positive findings from a pivotal phase III trial in which nab-paclitaxel 260 mg/m(2) every 3 weeks was superior to solvent-based paclitaxel 175 mg/m(2) every 3 weeks for the primary endpoint of overall response rate (33 % vs 19 %; P = 0.001). Subsequently, a number of trials have examined different schedules, doses, and combinations in efforts to optimize nab-paclitaxel-based therapy for metastatic and early-stage breast cancer. The goal of this review is to evaluate the clinical experiences to date with nab-paclitaxel as a single agent or in combination with targeted agents in different treatment settings - with a focus on the feasibility of administration, adverse event profile, and standard efficacy endpoints, such as overall survival, progression-free survival, overall response rate, and pathologic complete response rate. In general, weekly dosing during the first 3 of 4 weeks appears to achieve the best clinical benefit in both the metastatic and early-stage settings. Furthermore, the data suggest that high doses of nab-paclitaxel, such as 150 mg/m(2) during first 3 of 4 weeks or 260 mg/m(2) every 2 weeks, may be more feasible and appropriate for treatment of early-stage disease compared with metastatic disease. Intense regimens of nab-paclitaxel may not be the best treatment approach for unselected patients with metastatic breast cancer, but may suit a subset of patients for whom immediate disease control is required. The growing number of nab-paclitaxel trials in breast cancer will lead to greater refinements in tailoring therapy to patients based on their individual disease and patient characteristics.

The effect of paclitaxel and nab-paclitaxel in combination with anti-angiogenic therapy in breast cancer cell lines

Taxanes represent a treatment of choice for metastatic breast cancer. Their combination with bevacizumab improved response rate and progression-free survival. We studied in vitro the effect on cell survival of the combination of either paclitaxel or nab-paclitaxel with bevacizumab and we investigated the biological factors involved in the response to treatments. We used two breast cancer cell lines, MCF7 (ER+/HER2-) and MDA-MB-231 (ER-/HER2-), co-cultured with or without HUVEC cells. We analysed cell survival by MTT test, VEGF secretion by ELISA and VEGFR, SPARC, MDR1 expression by western blot. Doses of both taxanes causing a 50 % growth inhibition were higher in MCF7 than MDA-MB-231, suggesting that taxanes are more effective in ER- cell lines. When both cell lines were grown as single culture, the combination bevacizumab+paclitaxel showed a similar anti-proliferative effect compared to paclitaxel alone. The association bevacizumab+nab-paclitaxel was more effective than nab-paclitaxel alone. An increased anti-proliferative effect of bevacizumab+paclitaxel was observed when MDA-MB-231 cells were cultured with HUVEC. We detected an induction of VEGF secretion when MDA-MB-231 cells were treated with either taxanes. Paclitaxel caused a reduction of VEGF in MCF7. SPARC resulted up-regulated in both cell lines treated with bevacizumab+nab-paclitaxel. Nab-paclitaxel seems to play an important role in inhibiting tumor proliferation through albumin-SPARC bound in association with bevacizumab compared to taxanes alone in both breast cancer cells. The addition of bevacizumab to paclitaxel increased its activity only in ER- cells. This difference might be due to their ER status.

Overview of neuropathy associated with taxanes for the treatment of metastatic breast cancer

Taxanes are an established option in the standard treatment paradigm for patients with metastatic breast cancer (MBC). Neuropathy is a common, dose-limiting side effect of taxane therapy that is often managed by dose reductions and delays. The severity, time to onset, and improvement in neuropathy are important considerations for patient management and vary among currently approved taxanes. The rate of grade ≥3 neuropathy with taxanes has been shown to be dose and schedule dependent; however, time to improvement to grade ≤1 is typically shorter for nab-paclitaxel than for other taxanes in patients with MBC. Many tools for assessing patient-reported neuropathy exist. Because MBC is incurable and patient quality of life must be critically considered when making treatment decisions, there is a need for more prospective trials to assess patient-reported neuropathy. Validated predictors of taxane-related neuropathy may play an important role in treatment decisions in the future. This review will focus on the toxicity profile (i.e., neuropathy) of each of the taxanes used in the treatment of MBC, will provide updates on tools used for the assessment of neuropathy, and will highlight newly discovered predictors of taxane-related neuropathy.

Selecting first-line bevacizumab-containing therapy for advanced breast cancer: TURANDOT risk factor analyses

BACKGROUND

The randomised phase III TURANDOT trial compared first-line bevacizumab-paclitaxel (BEV-PAC) vs bevacizumab-capecitabine (BEV-CAP) in HER2-negative locally recurrent/metastatic breast cancer (LR/mBC). The interim analysis revealed no difference in overall survival (OS; primary end point) between treatment arms; however, progression-free survival (PFS) and objective response rate were significantly superior with BEV-PAC. We sought to identify patient populations that may be most appropriately treated with one or other regimen.

METHODS

Patients with HER2-negative LR/mBC who had received no prior chemotherapy for advanced disease were randomised to either BEV-PAC (bevacizumab 10 mg kg(-1) days 1 and 15 plus paclitaxel 90 mg m(-2) days 1, 8 and 15 q4w) or BEV-CAP (bevacizumab 15 mg kg(-1) day 1 plus capecitabine 1000 mg m(-2) bid days 1-14 q3w). The study population was categorised into three cohorts: triple-negative breast cancer (TNBC), high-risk hormone receptor-positive (HR+) and low-risk HR+. High- and low-risk HR+ were defined, respectively, as having ⩾2 vs ⩽1 of the following four risk factors: disease-free interval ⩽24 months; visceral metastases; prior (neo)adjuvant anthracycline and/or taxane; and metastases in ⩾3 organs.

RESULTS

The treatment effect on OS differed between cohorts. Non-significant OS trends favoured BEV-PAC in the TNBC cohort and BEV-CAP in the low-risk HR+ cohort. In all three cohorts, there was a non-significant PFS trend favouring BEV-PAC. Grade ⩾3 adverse events were consistently less common with BEV-CAP.

CONCLUSIONS

A simple risk factor index may help in selecting bevacizumab-containing regimens, balancing outcome, safety profile and patient preference. Final OS results are expected in 2015 (ClinicalTrials.gov NCT00600340).

Standard of care and promising new agents for triple negative metastatic breast cancer

Triple negative breast cancer (TNBC) is a cluster of heterogeneous diseases, all of them sharing the lack of expression of estrogen and progesterone receptors and HER2 protein. They are characterized by different biological, molecular and clinical features, including a poor prognosis despite the increased sensitivity to the current cytotoxic therapies. Several studies have identified important molecular features which enable further subdivision of this type of tumor. We are drawing from genomics, transcription and translation analysis at different levels, to improve our knowledge of the molecular alterations along the pathways which are activated during carcinogenesis and tumor progression. How this information should be used for the rational selection of therapy is an ongoing challenge and the subject of numerous research studies in progress. Currently, the vascular endothelial growth factor (VEGF), poly (ADP-ribose) polymerase (PARP), HSP90 and Aurora inhibitors are most used as targeting agents in metastatic setting clinical trials. In this paper we will review the current knowledge about the genetic subtypes of TNBC and their different responses to conventional therapeutic strategies, as well as to some new promising molecular target agents, aimed to achieve more tailored therapies.

Randomized phase II trial of weekly vs. every 2 weeks vs. every 3 weeks nanoparticle albumin-bound paclitaxel with bevacizumab as first-line chemotherapy for metastatic breast cancer

BACKGROUND

Nanoparticle albumin-bound paclitaxel (nab-P) and bevacizumab have each demonstrated efficacy in patients with MBC. This trial was designed to further develop nab-P by evaluating its efficacy and safety using every 3 weeks (q3w), every 2 weeks (q2w), or weekly scheduling in combination with bevacizumab as first-line treatment of MBC.

PATIENTS AND METHODS

This open-label phase II study randomized patients to nab-P 260 mg/m(2) q3w (arm A) vs. 260 mg/m(2) q2w with filgrastim (arm B) vs. 130 mg/m(2) weekly uninterrupted, all with bevacizumab (15 mg/kg q3w arm A, 10 mg/kg q2w arms B and C). The primary endpoints were overall response rate (ORR) and toxicity. Time to tumor progression (TTP) and overall survival were secondary endpoints.

RESULTS

Of 212 patients randomized, 208 (arm A, 75; arm B, 54; arm C, 79) were treated. Arm B was closed early due to toxicity, with more grade ≥ 2 fatigue (arm A, 46%; arm B, 62%; arm C, 62%) and bone pain (arm A, 11%; arm B, 23%; arm C, 5%). Neurotoxicity grade ≥ 2 was equivalent across the arms (> 50%) and reversible for most patients. Febrile neutropenia occurred in ≤ 3% of patients in all arms. ORR was similar among the arms (arm A, 45%; arm B, 41%; arm C, 46%). Median TTP was slightly longer in arm C (9.0 months) vs. arms A (8.0 months) and B (5.8 months) (overall, P = .105).

CONCLUSIONS

Significant antitumor activity was observed in all the arms. Weekly nab-P with bevacizumab appeared to have the highest therapeutic index. However, sensory neuropathy was treatment limiting, which suggests that a 3 weeks on and 1 week off schedule should be explored.

Phase II randomized trial of weekly and every-3-week ixabepilone in metastatic breast cancer patients

This multicenter, open-label, randomized phase II trial compared the efficacy and tolerability of weekly ixabepilone versus the standard 3 weekly dosing regimen. Patients with human epidermal growth factor receptor 2-negative, metastatic breast cancer (MBC) were randomly assigned to receive either ixabepilone 16 mg/m(2) as a 1-h intravenous (IV) infusion weekly on days 1, 8, and 15 of a 28-day cycle (1 week off therapy; n = 85), or 40 mg/m(2) as a 3-h IV infusion on day 1 of a 21-day cycle (n = 91), until disease progression or unacceptable toxicity. Randomization was stratified by (i) measurable versus nonmeasurable (evaluable) disease, (ii) ≤two versus >two prior chemotherapy regimens for MBC, and (iii) hormone receptor (HR)-positive versus HR-negative breast cancer. The primary endpoint was rate of progression-free survival (PFS) at 6 months. Of 176 randomized patients, 171 were treated. The 6-month PFS rate was significantly higher in patients treated with ixabepilone every 3 weeks (42.7, 95 % confidence interval [CI] 31.5-53.5) compared with those who received ixabepilone weekly (28.6, 95 % CI 18.9-38.9; log-rank P = 0.03). Every-3-week dosing significantly prolonged median PFS versus weekly dosing (5.3 vs. 2.9 months; log-rank P = 0.05). The every-3-week regimen was associated with higher rates of grade 3/4 toxicities, particularly neutropenia (38.2 vs. 6.1 %) and a higher rate of patient withdrawal due to adverse events. These results suggest that every-3-week ixabepilone is more effective than weekly treatment in MBC, albeit with more toxicity.

Eribulin mesylate versus ixabepilone in patients with metastatic breast cancer: a randomized Phase II study comparing the incidence of peripheral neuropathy

Peripheral neuropathy is a common toxicity associated with tubulin-targeted chemotherapeutic agents. This Phase II study compares the incidence and severity of neuropathy associated with eribulin mesylate or ixabepilone in metastatic breast cancer (MBC). The primary objective was to assess the incidence of neuropathy; the study was designed to detect a difference in neuropathy rate of 35 % for eribulin versus 63 % for ixabepilone (odds ratio 0.316, 80 % power, 0.05 two-sided significance level). Eligibility criteria included: MBC; prior taxane therapy; at least one chemotherapy for advanced disease; no or minimal pre-existing neuropathy (Grade 0 or 1). The intent-to-treat population comprised 104 patients randomized (1:1) to eribulin mesylate (1.4 mg/m², 2–5 min intravenous on days 1 and 8) or ixabepilone (40 mg/m², 3 h intravenous on day 1) on a 21-day cycle. 101 patients in the safety population received a median of 5.0 eribulin and 3.5 ixabepilone cycles. Incidence of neuropathy (any grade) was 33.3 and 48.0 %, and peripheral neuropathy was 31.4 and 44.0 % for eribulin and ixabepilone, respectively. After controlling for pre-existing neuropathy and number of prior chemotherapies, these differences were not significant. Compared with ixabepilone, fewer patients receiving eribulin discontinued treatment due to neuropathy (3.9 vs. 18.0 %) or adverse events (AEs) in general (11.8 vs. 32.0 %). Time to onset of neuropathy was 35.9 weeks for eribulin and 11.6 weeks for ixabepilone, and time to resolution was 48 versus 10 weeks, respectively; other AEs were comparable. Objective responses were 15.4 versus 5.8 % and clinical benefit rates were 26.9 versus 19.2 %. In conclusion, after controlling for pre-existing neuropathy and number of prior chemotherapies, the differences in the incidence of neuropathy with eribulin and ixabepilone were not statistically significant. Onset of neuropathy tended to occur later with eribulin and resolve later.

Safety of nanoparticle albumin-bound paclitaxel administered to breast cancer patients with clinical contraindications to paclitaxel or docetaxel: Four case reports

Taxanes, including paclitaxel (PTX) and docetaxel (DOC), are poorly soluble in water due to their hydrophobic properties and thus, require solvents. However, use of these solvents has been associated with toxic responses, including a hypersensitivity reaction (HSR). Nanoparticle albumin-bound paclitaxel (nab-PTX) is a novel formulation of PTX, which allows reconstitution of the agent with a saline solution instead of solvents and administration without premedication for HSRs. The current study reports the safe administration of nab-PTX to four breast cancer patients considered clinically to have contraindications to PTX or DOC. Two of the patients had previously experienced HSRs to PTX or DOC and the other two patients had contraindications to steroids as a premedication for HSRs, since one patient suffered from diabetes and the other was a carrier of the hepatitis B virus. All 4 patients were safely administered nab-PTX. In conclusion, administration of nab-PTX appears to be effective for patients that have previously experienced HSRs to other taxanes or in those with contraindications to steroids.

Defining risks of taxane neuropathy: insights from randomized clinical trials

Sensory neuropathy is a common but difficult to quantify complication encountered during treatment of various cancers with taxane-containing regimens. Docetaxel, paclitaxel, and its nanoparticle albumin-bound formulation have been extensively studied in randomized clinical trials comparing various dose and schedules for the treatment of breast, lung, and ovarian cancers. This review highlights differences in extent of severe neuropathies encountered in such randomized trials and seeks to draw conclusions in terms of known pharmacologic factors that may lead to neuropathy. This basic knowledge provides an essential background for exploring pharmacogenomic differences among patients in relation to their susceptibility of developing severe manifestations. In addition, the differences highlighted may lead to greater insight into drug and basic host factors (such as age, sex, and ethnicity) contributing to axonal injury from taxanes.

A randomized, phase II, three-arm study of two schedules of ixabepilone or paclitaxel plus bevacizumab as first-line therapy for metastatic breast cancer

The aim of this phase II trial was to estimate the objective response rate (ORR) of two different schedules of ixabepilone [weekly or every 3 weeks (Q3W)] combined with bevacizumab, relative to a reference arm of weekly paclitaxel and bevacizumab. Patients with human epidermal growth factor receptor 2-normal, chemotherapy-naïve metastatic breast cancer (MBC) were randomized 3:3:2 to ixabepilone 16 mg/m(2) weekly plus bevacizumab 10 mg/kg Q2W (Arm A: n = 46); ixabepilone 40 mg/m(2) Q3W (reduced to 32 mg/m(2) after four cycles of treatment) plus bevacizumab 15 mg/kg Q3W (Arm B: n = 45); or paclitaxel 90 mg/m(2) weekly plus bevacizumab 10 mg/kg intravenous infusion Q2W (Arm C: n = 32). Of 123 randomized patients, 122 were treated. All were followed for ≥19 months; 5 % of patients remained on study treatment at the time of this analysis. Grade 3 or 4 neutropenia was more common in Arm B (60 %) than Arms A (16 %) or C (22 %); other adverse events were similar. The investigator-assessed ORR was 48, 71, and 63 % for Arms A, B, and C, respectively. Median progression-free survival (randomized patients) was 9.6 months in Arm A, 11.9 months in Arm B, and 13.5 months in Arm C. In conclusion, ixabepilone Q3W plus bevacizumab has clinical activity as first-line therapy for MBC relative to paclitaxel plus bevacizumab, but with significantly greater risk of grade 3 or 4 neutropenia. In addition, these data suggest that weekly dosing of ixabepilone may be less active than Q3W dosing, but with less neutropenia.

Nab-paclitaxel for first-line treatment of patients with metastatic breast cancer and poor prognostic factors: a retrospective analysis

Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) has demonstrated clinical benefit in metastatic breast cancer (MBC) in a randomized phase III trial versus paclitaxel (CA012; N = 454) and in a randomized phase II trial versus docetaxel (CA024; N = 300). This retrospective analysis examines whether patients with poor prognostic factors demonstrate similar outcomes to the intent-to-treat (ITT) populations in these trials. This retrospective analysis evaluated the efficacy and safety of previously untreated patients with MBC with the following poor prognostic factors: visceral dominant metastases and short disease-free interval (DFI; ≤2 years). In CA012 (n = 186 first-line patients), nab-paclitaxel demonstrated a significantly higher overall response rate (ORR) versus paclitaxel in patients with visceral dominant metastases (42 vs. 23 %; P = 0.022), whereas the higher ORR for nab-paclitaxel in patients with a short DFI (43 vs. 33 %; P = NS) was not statistically significant. In CA024, a significantly higher ORR for nab-paclitaxel 150 mg/m² versus docetaxel was observed in patients with visceral dominant metastases (76 vs. 37 %; P < 0.001). No significant differences in ORR were observed in patients with a short DFI. Although progression-free survival (PFS) and overall survival showed trends similar to ORR, statistical significance was only achieved for comparisons of PFS in patients with visceral dominant metastases in CA024 (13.1 months for nab-paclitaxel 150 mg/m² vs. 7.8 months for docetaxel [P = 0.019] and 7.5 months for nab-paclitaxel 100 mg/m² [P = 0.010]). Safety results were similar to previous reports of the ITT populations. nab-Paclitaxel demonstrated similar efficacy in patients with poor prognostic factors as in the ITT populations of these two trials. In each trial, ORR was significantly higher for nab-paclitaxel versus the comparator taxane among patients with visceral dominant metastases.

Biomarker analysis of neoadjuvant doxorubicin/cyclophosphamide followed by ixabepilone or Paclitaxel in early-stage breast cancer

PURPOSE

Predictive biomarkers offer the potential to improve the benefit:risk ratio of a therapeutic agent. Ixabepilone achieves comparable pathologic complete response (pCR) rates to other active drugs in the neoadjuvant setting. This phase II trial was designed to investigate potential biomarkers that differentiate response to this agent.

EXPERIMENTAL DESIGN

Women with untreated, histologically confirmed primary invasive breast adenocarcinoma received neoadjuvant doxorubicin/cyclophosphamide, followed by 1:1 randomization to ixabepilone (n = 148) or paclitaxel (n = 147). Rates of pCR were compared between treatment arms based on predefined biomarker sets: TUBB3, TACC3, and CAPG gene expression, a 20- and 26-gene expression model, MDR1 protein expression, and other potential markers of sensitivity. βIII-tubulin protein expression is reported separately but is referred to here for completeness. All patients underwent a core needle biopsy of the primary cancer for molecular marker analysis before chemotherapy. Gene expression profiling data were used for molecular subtyping.

RESULTS

There was no significant difference in the rate of pCR in both treatment arms in βIII-tubulin-positive patients. Higher pCR rates were observed among βIII-tubulin-positive patients than in βIII-tubulin-negative patients. Furthermore, no correlation was evident between TUBB3, TACC3, and CAPG gene expression, MDR1 protein expression, multi-gene expression models, and the efficacy of ixabepilone or paclitaxel, even within the estrogen receptor-negative subset.

CONCLUSION

These results indicate that βIII-tubulin protein and mRNA expression, MDR1 protein expression, TACC3 and CAPG gene expression, and multigene expression models (20- and 26-gene) are not predictive markers for differentiating treatment benefit between ixabepilone and paclitaxel in early-stage breast cancer.